The Federal Government (if they had any balls) should try to press criminal charges against the ACLU for aiding or assisting illegal aliens crossing the border (as an infringement of Congress's Police Power). If anything, it might bring to light the seriousness of the ACLU's actions and turn more people against them. It also might force the Feds to answer up to the people regarding how many illegal aliens make it over every year. Not likely to happen. Whoever posted the RICCO violation idea has something going as well.
...or obstruction of justice...